13,265 research outputs found

    Bi-fuel NGVM engine emission results based on non-loaded system operation

    Get PDF
    Alternative fuels for the internal combustion engines are introduced as an improved fuel over mainstream conventional fuels such as petrol and diesel. Compressed Natural Gas (CNG) is the most successful and widely used alternative fuels that helps mitigate emission problem caused by vehicles. Mainstream fuelled vehicles are fitted with a conversion kit to enable the operation with CNG, these converted vehicles are called Natural Gas Vehicles. A bi-fuel engine test rig was fabricated using a 1500cc 12 Valve engine fitted with a Landi Renzo conversion kit enabling operations on petrol and natural gas. This test rig was used to conduct experiments to obtain the fuel consumption and the corresponding exhaust emission quality. The results obtained were compared with the actual data of NGV taxi fitted with Tartarini conversion kit for validation purpose. The findings from this experimental rig are used as a comparison between the use of petrol and natural gas as fuel for vehicles. The results clearly prove that the use of natural gas provides improved exhaust emission at lower cos

    Computational method to predict thermodynamic, transport, and flow properties for the modified Langley 8-foot high-temperature tunnel

    Get PDF
    The Langley 8 foot high temperature tunnel (8 ft HTT) is used to test components of hypersonic vehicles for aerothermal loads definition and structural component verification. The test medium of the 8 ft HTT is obtained by burning a mixture of methane and air under high pressure; the combustion products are expanded through an axisymmetric conical contoured nozzle to simulate atmospheric flight at Mach 7. This facility was modified to raise the oxygen content of the test medium to match that of air and to include Mach 4 and Mach 5 capabilities. These modifications will facilitate the testing of hypersonic air breathing propulsion systems for a wide range of flight conditions. A computational method to predict the thermodynamic, transport, and flow properties of the equilibrium chemically reacting oxygen enriched methane-air combustion products was implemented in a computer code. This code calculates the fuel, air, and oxygen mass flow rates and test section flow properties for Mach 7, 5, and 4 nozzle configurations for given combustor and mixer conditions. Salient features of the 8 ft HTT are described, and some of the predicted tunnel operational characteristics are presented in the carpet plots to assist users in preparing test plans

    Combinatorial FSK modulation for power-efficient high-rate communications

    Get PDF
    Deep-space and satellite communications systems must be capable of conveying high-rate data accurately with low transmitter power, often through dispersive channels. A class of noncoherent Combinatorial Frequency Shift Keying (CFSK) modulation schemes is investigated which address these needs. The bit error rate performance of this class of modulation formats is analyzed and compared to the more traditional modulation types. Candidate modulator, demodulator, and digital signal processing (DSP) hardware structures are examined in detail. System-level issues are also discussed

    Stabilisation and solidification of contaminated soil using cement and sugarcane bagasse ash (SCBA)

    Get PDF
    Soil that is contaminated with heavy metals has become a major issue worldwide. However, proper remediation techniques such as stabilisation/solidification (S/S) method can be employed and is capable of controlling these heavy metals. Conventionally, the common S/S method used cement as binder on remediating the contaminated soil particularly heavy metals. This research is to investigate the effect of physical and leachability of contaminated soil in S/S method when Sugarcane Bagasse Ash (SCBA) is added to remedy contaminated soil. Landfill contaminated soil was used to test the effectiveness of those binder. Cement was added at a proportion of 5%, 10%, 15% and 20% in sample weights without SCBA while in another sample; the cement was replaced by SCBA at a proportion of 2.5%, 5%, 7.5% and 10%. All samples are to be allowed to harden and cured at room temperature for 7, 14 and 28 days. The effectiveness of the treatment was assessing by conducting physical testing such as Unconfined Compression Strength, Water Absorption and Permeability test. In addition, leaching tests were performed to identify the leachate behavior of heavy metals during treatment. Three leaching tests were conducted and they were the Toxicity Characteristic Leaching Procedure (TCLP), Synthetic Precipitation Leaching Procedure (SPLP) and Dynamic Leaching Test (DLT). Through the physical testing, samples containing 10% OPC mixed with 10% SCBA were found to improve the compressive strength, reduced the water absorption and water permeability measuring 1550 MPa, 17.94% and 4.41 x 10 -10 m/s respectively. In the same way, through the statistical analysis, the R-squared for UCS with respect to mixed design is high at 98%. However, the value for both water absorption and permeability recorded to be marginally low, compared to the value for strength at 89% and 88% respectively. Through the TCLP and SPLP test, results indicated that when SCBA added to OPC content in soil samples, less heavy metal been leached out from the S/S sample. In average, the satisfying result was shown by samples containing 10% OPC + 10% SCBA where reduction of heavy metals in final leachate is more than 90% for As, Cd, Cr, Pb and Zn. Through the Dynamic Leaching Test, sample containing 10% OPC +10% SCBA showed the satisfactory leachability index (Lx) at 9.17, 9.17, 8.81, 8.17 and 6.97 for As, Cd, Cr, Pb and Zn respectively. This indicates that the use of cement and SCBA as a binder was successful in remediating the contaminated soils through the S/S method

    Materials and Mix Optimization Procedures for PCC Pavements;TR-484, March 2006

    Get PDF
    Severe environmental conditions, coupled with the routine use of deicing chemicals and increasing traffic volume, tend to place extreme demands on portland cement concrete (PCC) pavements. In most instances, engineers have been able to specify and build PCC pavements that met these challenges. However, there have also been reports of premature deterioration that could not be specifically attributed to a single cause. Modern concrete mixtures have evolved to become very complex chemical systems. The complexity can be attributed to both the number of ingredients used in any given mixture and the various types and sources of the ingredients supplied to any given project. Local environmental conditions can also influence the outcome of paving projects. This research project investigated important variables that impact the homogeneity and rheology of concrete mixtures. The project consisted of a field study and a laboratory study. The field study collected information from six different projects in Iowa. The information that was collected during the field study documented cementitious material properties, plastic concrete properties, and hardened concrete properties. The laboratory study was used to develop baseline mixture variability information for the field study. It also investigated plastic concrete properties using various new devices to evaluate rheology and mixing efficiency. In addition, the lab study evaluated a strategy for the optimization of mortar and concrete mixtures containing supplementary cementitious materials. The results of the field studies indicated that the quality management concrete (QMC) mixtures being placed in the state generally exhibited good uniformity and good to excellent workability. Hardened concrete properties (compressive strength and hardened air content) were also satisfactory. The uniformity of the raw cementitious materials that were used on the projects could not be monitored as closely as was desired by the investigators; however, the information that was gathered indicated that the bulk chemical composition of most materials streams was reasonably uniform. Specific minerals phases in the cementitious materials were less uniform than the bulk chemical composition. The results of the laboratory study indicated that ternary mixtures show significant promise for improving the performance of concrete mixtures. The lab study also verified the results from prior projects that have indicated that bassanite is typically the major sulfate phase that is present in Iowa cements. This causes the cements to exhibit premature stiffening problems (false set) in laboratory testing. Fly ash helps to reduce the impact of premature stiffening because it behaves like a low-range water reducer in most instances. The premature stiffening problem can also be alleviated by increasing the water–cement ratio of the mixture and providing a remix cycle for the mixture

    Exploratory Research on MEMS Technology for Air-Conditioning and Heat-Pumps

    Get PDF
    This report details the efforts to exploit micro-electrical-mechanical-systems (MEMS) and micro device technologies to improve control of multi-channel evaporators by reducing maldistribution among channels, and increase capacity and efficiency of current vapor-compression refrigeration chillers and heat-pumps. Besides summarizing the market potential of MEMS technology for use in evaporators and micro-heat-pumps, the report describes the accomplishments of an experimental investigation of refrigerant-side maldistribution in multi-channel plate heat exchangers (PHE's). A special test facility designed for the purpose of studying the maldistribution of refrigerant in evaporators is described in the report. The facility allows maldistribution caused by either normal superheat temperature control, or induced by the user in controlled amounts, to be measured and quantified. Four different techniques were used to detect the presence of liquid droplets in the stream of superheated vapor at the evaporator exit, an indication of maldistributed flow. They are: Helium-Neon laser, beaded thermocouple, static mixer and newly designed heated MEMS sensor. Comparison of the four techniques shows that the MEMS sensor designed and fabricated in this project has the highest potential for indicating maldistribution, manifested by entrained liquid droplets, in multi-channel evaporators. A complete set of test results in the time and frequency domain is show in graphical form in the appendices. The design, fabrication, calibration, and testing of the MEMS serpentine resistance sensor is also reported, along with a control scheme and strategy for implementing the MEMS sensor in multi-channel evaporator systems

    Evaluating the Effects of Modifying Mixing and Pelleting Parameters on Feed Quality, Pellet Production Rate, and Broiler Performance

    Get PDF
    In Chapter 2, an experiment was conducted to evaluate the effect of different mixer types (MTY) and mix times (MTI) on mix uniformity (MU). A 2 (mix time) x 3 (mixer type) factorial was utilized in this experiment to create six treatments, each mixed in three randomized complete blocks. Mix times were designated adequate or inadequate, were based on the manufacturers’ recommendation, and varied based on the mixer utilized. The mixer types utilized included a vertical mixer, horizontal mixer, and transfer mixing system. The transfer mixing system can be described as a batch-to-mix system that simulates the process of conveying batched feed to a mixing location. Chloride ions (Cl-) via salt, crystalline DL-Methionine (Free Met), and crystalline L-Lysine-HCL (Free Lys) were utilized as coefficient of variation (CV) markers, with Cl- being used in a corn-salt (CS) ration and the Free Met and Free Lys being used in a complete diet (CD). An interaction between MTY and MTI affected Free Met CV (P = 0.005). The horizontal mixer and transfer mixing system did not demonstrate changes in the Free Met CV compared to the vertical mixer when MTI was manipulated. The authors hypothesize that additional mixing during load-out and added conveyance caused this interaction. The transfer mixing system resulted in the lowest Free Lys CV (P = 0.017); however, no treatment provided an industry-acceptable MU. In conclusion, Free Lys may not be an appropriate marker for MU, Free Met may be an appropriate marker for MU in complete diets, and the transfer mixing system may contribute to an acceptable MU. In Chapter 3, an experiment was conducted to evaluate the influence of pellet die thickness (PDT) and Azomite® (AZM) on feed manufacture. A 2 (AZM) x 3 (PDT) factorial was utilized in this experiment to create a total of six treatments, each manufactured in every run order position in a Latin Square Design. Azomite inclusion rate was either 0.0% (control) or 0.25%, and 32mm, 38mm, and 45mm PDTs were utilized in their appropriate treatments. The pellet diameter was held to a constant of 4.5mm. The objective of this study was to evaluate the effect of AZM and PDT on pellet production rate (PPR), pellet durability index (PDI), and hot pellet temperature (HPT) in corn, soybean meal, and dried distillers grains with solubles-based poultry diets, manufactured under a constant motor load. The inclusion of AZM increased overall PPR by 7.9% (P \u3c 0.001) and decreased overall PDI by 1.6 percentage points (P \u3c 0.001). As PDT increased from 32mm to the average of the 38 and 45mm treatments, PPR decreased by 28.5% (P \u3c 0.001) and increased PDI by 10.1 percentage points (P \u3c 0.001). A main effect interaction of AZM and PDT was recognized to influence HPT (P \u3c 0.007), however, no difference was observed for the 45mm PDT when AZM was included. Linear contrasts showed that PPR increased by 5.0, 7.9, and 11.8% when comparing AZM treatments to their respective controls (All PDT; P \u3c 0.001). The authors of this experiment concluded that AZM increased PPR across PDT and decreased PDI, albeit to the extent that would likely not affect broiler performance. In Chapter 4, a follow-up experiment to the previous was conducted to evaluate the influence of PDT and AZM inclusion rate on broiler performance and apparent ileal amino acid digestibility (AIAAD). A 2 (AZM) x 2 (PDT) factorial was utilized in this experiment to create a total of four treatments. The dietary treatments were sourced from the previous AZM experiment, and only the treatments utilizing the 32 and 45mm PDT were utilized. All feed was reground and slightly reformulated to reduce the confounding bias of PDI and to ensure an acceptable nutritional density. Ten randomized complete blocks of raised wire cages were utilized with each pen housing ten Ross 308 broilers. The objective of the study was to determine the effect of pelleted feed using AZM (0.0 or 0.25%) and PDT (32 or 45mm; using a constant die diameter of 4.5mm) on Ross 308 male broiler feed intake, live weight gain, feed conversion ratio, and AIAAD from 0 to 21 days of age. Live performance did not differ due to an interaction or independent main effects (P \u3e 0.05). However, AIAAD was influenced by AZM and PDT interactions (P \u3c 0.05). The amino acids Ala, Asp, Glu, Gly, Ile, Lys, Met, Pro, Thr, and Val demonstrated increased digestibility with the 45mm Control treatment. This treatment also produced the highest numerical HPT in the feed manufacture experiment. It was hypothesized that the digestibility resulted from increased frictional heat that deactivated trypsin and chymotrypsin inhibitors or degraded ingredient cell wall structure. While both inhibitors were determined to be present using SDS-PAGE and chemiluminescent detection, quantitative analysis showed no practically influential concentrations of either inhibitor or a decrease large enough to explain the increased AIAAD. The authors, therefore, speculate that the increase in AIAAD of various amino acids was due to the breakdown of the aleurone layer cell walls of the corn kernels caused by increased frictional heat exposure vis the 45mm PDT and the absence of AZM

    Improving Broiler Performance Utilizing Modern Feed Additives

    Get PDF
    Modern broiler production strives to make modest improvements regarding broiler performance. This remains a goal as global population increases thusly increasing the quantity of an affordable, high quality source of protein. In recent years, an added stressor to achieving prior goals is mostly related to consciousness of environmental and consumer health. For decades, integrators have utilized minimal amounts of antibiotics as a barrier to most pathogens affecting the microbiome of a broiler’s gastrointestinal tract. Regulatory efforts have now prohibited most of previous sub-therapeutic medicine and started an in-depth scope of broiler gut health and interaction with antibiotic alternatives. In an effort to provide beneficial bacteria in a challenged environment, broilers were fed Direct-Fed Microbials (DFM), notably Bacillus subtilis, to investigate performance improvements. Diets were formulated to meet bird requirements during specific age periods. 2,280 male Ross x Ross 708 broilers were placed on study for 42 days to evaluate live performance. Pens of 23 broilers were randomly assigned one of four dietary treatments; a control diet, and 3 diets compromised of the control and an additional top dressed DFM. A natural challenge was manifested by a combination of built-up litter and a weekly water spray to facilitate bacterial growth. Additionally, the diet was nutritionally limited. The results revealed that dietary treatments performed the same for most measurements. Live weight gain decreased in diets containing DFM2 or DFM3. Overall, broilers performed below industry expectations in each performance variable, suggesting the additive effect of nutritional deficit, floor conditions, and heat stress may have hindered opportunity for DFMs to perform or provide enough stimulus to generate expected results. Additionally, transgenic grains were implemented into broiler diets to identify ability to liberate Ca and P by expressing phytase at two different concentrations. Different expressions resulted in volume discrepancies. Distribution throughout a mixer was of interest to identify potential for minimizing dietary inclusion thusly total cost. Phytase has long been utilized to combat P excretion in the poultry industry related to environmental concerns. Grain-expressed enzymes allow for a direct 1:1 replacement for the host grain. Adding exogenous enzymes without diluting dietary nutrients will be another means of improving performance by maximizing nutrient utilization. 2,304 male Ross x Ross 708 broilers were obtained and placed in pens of 24. A dietary factorial treatment structure was utilized for two corn-expressed phytase products at three doses. Additionally, a positive and negative control were used. Birds were selected randomly at day 21(n=5) and day 42(n=3), to be euthanized for tibia excision. Tibiae were collected, ashed and bone mineralization was determined to quantify liberation of additional P/Ca. Live performance was also measured. Results showed that a lower concentrated grain enzyme requires more volume and has more opportunity to distribute evenly during batching of a diet. This is reinforced by performance results that yield improved LWG for a product that requires more volume for a target dose

    Feed Quality Effects on Modern Heavy Broiler Performance

    Get PDF
    Commercial broilers are fed exclusively pelleted diets; this is due to research that has demonstrated numerous benefits to feeding pellets. The first objective was to investigate the effects of modest improvements in pellet quality on two modern broiler strains. Regardless of strain, feeding 80% pellets improved broiler performance from d 28 to 42. The second objective was to investigate the effects of feed form and liquid application method on feed augering segregation and subsequent broiler performance. In general, percent pellets steadily decreased across location throughout feed augering. Also, phytase segregation occurred throughout augering and was exacerbated in post-pellet liquid application diets. When the augered diets were fed to broilers, 75% pellets and post-pellet liquid application diets improved performance. The final objective was to investigate the change in percent pellets as feed was augered throughout an entire commercial poultry house. Ultimately, creating high-quality pellets decreases pellet attrition and improves broiler performance
    • …
    corecore